A semiconductor memory includes a volatile memory such as a DRAM (Dynamic Random Access Memory) and a non-volatile memory such as a flash memory. As the non-volatile memory, a NAND type flash memory is known. For more miniaturization, a resistance change device (ReRAM: Resistance RAM) draws the attention.
The resistance change device has a variable resistor where resistivity is changed reversibly depending on a voltage, and can store data in a non-volatile way corresponding to a high resistance state or a low resistance state. The resistance change device has features such as a high-speed operation and a low power consumption.
However, the resistance change device may generate an excess current upon a switching operation (a state transition from the high resistant state to the low resistant state), which may cause device breakage or may lower reliability of the device. In order to prevent this, there is a known technology that an external resistance is inserted to a switching circuit and the excess current is prevented from flowing to the device. For example, Patent Document 1 describes a resistance change non-volatile memory having a current limiting circuit including a diode.
Patent Document 1: Japanese Patent No. 4643767 (paragraph [0231], FIG. 21)